ABSTRACT
This chapter deals with the preparation of soluble derivatives such as water-soluble chitin, tosyl-chitin, iodo-chitin, and N-phthaloyl-chitosan, and some efficient chemical modifications of these precursors in solution. Chitin is reported to be soluble in N,N-dimethylacetamide containing lithium chloride, but the extent of solubility is dependent on the origins of chitin. Chitin can be dissolved in aqueous alkali by steeping in concentrated sodium hydroxide followed by treating with crushed ice to give an alkali chitin solution. The water-soluble chitin is useful as a reactive precursor for controlled modifications, since the reactions can be performed in a homogeneous aqueous solution or in a highly swollen state in organic solvents. Owing to the high solubility and reactivity of tosyl- and iodo-chitins, they are promising as reactive precursors for various modification reactions in homogeneous solution in organic solvents. Biodegradability is one of the important aspects of chitin derivatives, and the mercapto-chitins have turned out to be more susceptible to lysozyme than the original chitin.
